This invention relates to a liquid containment device with a self-contained pump for dispensing liquid in small doses of a predetermined volume. More particularly, this invention relates to a replaceable containment device of the foregoing character which is useful in an ink-jet printer for containing a supply of printing ink and for dispensing the printing ink to a printing head upon the actuation of the self-contained pump.
A U.S. patent application, which is being filed contemporaneously herewith by Bruce Cowger and Norman Pawlowski, Jr. for an invention entitled xe2x80x9cInk Supply For An Ink-Jet Printer,xe2x80x9d describes an ink supply for an ink-jet printer that is separate from the printer ink pen, and can be replaced upon the emptying of the ink supply without the need to replace the printer ink pen. The ink supply of the aforesaid U.S. patent application incorporates a self-contained pumping device for dispensing ink from a pumping chamber, and describes, as an embodiment of such a pumping device, a bellows pump. However, a bellows pump requires a relatively large extended surface of a semi-rigid material, such as a polymeric material, and is subject to a relatively high rate of oxygen and moisture transfer through the material of the bellows. This oxygen and/or moisture transfer can result in the degradation of the ink within the ink supply, especially in a printer that is used only infrequently. Further, the bellows is subject to leakage at the location of its attachment to another portion of the ink supply. However, these and other problems associated with the use of a bellows can be avoided by the use of a pumping device having a rigid perimetrical wall, preferably formed integrally with the associated chassis structure of the ink supply, with a linearly acting pumping member that is moveable within a pumping chamber defined by the rigid wall to pressurize ink within the pumping chamber, and a flexible moisture and oxygen barrier film heat sealed to an edge of the perimetrical wall in a continuous pattern and overlying the pumping member.
An ink supply according to the aforesaid U.S. patent application also has a generally cup-shaped outer shell of a fairly rigid polymeric material, preferably a material with translucent properties to permit inspection of the contents thereof, which is used to contain and protect a flexible, ink-containing pouch. The outer shell is generally rectangular in cross-section, with an opposed pair of very long sides and an opposed pair of very short sides, the configuration of the shell being determined by the design of a docking station of the printer into which the ink supply is to be inserted when it is in position for the dispensing of ink therefrom. In such an arrangement, the very long sides of such a shell are subject to warpage, which can interfere with the assembly of the ink supply into the docking station. However, it has been found that such warpage problems can be overcome by constructing the ink supply shell with an outwardly projecting bow or convex configuration, so that the cross-section configuration of the shell is approximately part elliptical rather than rectangular.
In an ink supply according to the aforesaid U.S. patent application, there is also provided a chassis to be affixed to the open end of the shell. This chassis, which houses the pump of the ink supply and has a fluid outlet for the dispensing of ink from the ink supply, must be secured to the shell in such a way that it cannot be readily disengaged therefrom. Of necessity, the chassis has a complex configuration, but can readily be formed in a single piece in such complex configuration from a polymeric material by injection molding. Of course, the chassis and the shell can be secured to each other by heat sealing if they are formed from compatible polymeric materials, but such a heat sealing step is time-consuming and expensive. However, the heat sealing step can be avoided by a snap fit between the shell and the chassis when the chassis is constructed in the form of a plug that fits snugly within the upper portion of the open end of the shell. Such a snap fit is particularly effective when the shell is constructed with an approximately part-elliptical cross-sectional configuration, as described above. While the use of a snap fit in this manner does not provide a true hermetic seal within the interior of the shell, it does retard the flow of air and moisture into and out of the shell to a sufficient extent to avoid posing degradation problems for an ink supply contained within a sealed, flexible pouch packaged within and protected by the outer shell.
An ink supply according to the aforesaid U.S. patent application also incorporates a cap of a complex configuration that is secured to the polymeric chassis, after the chassis and the flexible pouch, which is attached to the chassis, is secured to the shell with the flexible pouch contained within the shell. Because of the complexity of the cap, it is preferably formed integrally in a single piece from a polymeric material by injection molding. In any case, it is preferred that the attachment of the cap to the chassis be tamper resistant, which requires a relatively high degree of permanency to such attachment. However, it has been found that the requisite permanency in the attachment of a polymeric cap to the chassis can be readily and inexpensively obtained by providing the chassis with a spaced apart pair of outwardly projecting studs that are integrally formed with the chassis, and by providing the cap with a spaced apart pair of apertures that are aligned with the studs and receive the studs therein such that the free ends of the studs extend through the apertures in the cap and are accessible by a deforming tool such as a heated softening tool. After the attachment of the cap to the chassis, the free ends of the studs are deformed by heating them with the heat softening tool, to form buttons or caps that have outer diameters greater than the inner diameter of the apertures in the cap, thereby making it very difficult to disengage the cap from the chassis.
Accordingly, it is an object of the present invention to provide an improved liquid containing and dispensing device. More particularly, it is an object of the present invention to provide an improved device of the foregoing character that is useful in containing and dispensing ink in an ink-jet printer.
It is also an object of the present invention to provide a liquid containment and dispensing device with an improved, self-contained pumping device. More particularly, it is an object of the present invention to provide an improved device of the foregoing character that is useful in containing and dispensing ink in an ink-jet printer.
It is also an object of the present invention to provide a printing ink containment and dispensing device for an ink-jet printer having a rigid, polymeric shell of a generally rectangular cross-section that contains a flexible, ink-containing pouch, in which the longer sides of the shell are resistant to warpage. More particularly, it is an object of the present invention to provide an improved ink containment and dispensing device of the foregoing character which can be readily assembled to an associated chassis structure without the need for heat sealing the rigid shell and the chassis structure to one another.
For a further understanding of the present invention and the objects thereof, attention is directed to the drawing and the following brief description thereof, to the detailed description of the preferred embodiment of the invention, and to the appended claims.